sir tony
i will quote this
the secret, if you can call it as such is in the power supply....i used 47,000ufd electrolytics, a 35 ampere rectifier bridge and very heavy power transformers whose secondaries are wound bifilliar to exactly locate the center tap, about twice as heavy as other commercial power traffos...
how to do it
the bifiliar?

bifilliar winding is done by winding 2 strands of copper wire at the same time, since they are wound side by side, they will have exactly the same turns and therefore the center tap is exactly located...

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the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....

there were 7 participants this year in the "junior category", one 15 or 18 inch woofer, then for mid highs there is no limit....the amps also have no limit, there were crown amps, Konzert amps, there were even pioneer recievers.....almost all used bi-amping, many has tube preamps, the AR sp3 tubed clones....

@engel,

i saw only one tube amp used, a pp KT88 used to power the mids and highs, but is was rather disappointed in its performance,

all amps are welcome......

__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....